Hydraulically powered drilling sub



April 1, 1969 G'ILREATH ET AL 3,435,732

' HYDRAULICALLY POWERED DRILLING SUB Filed July 15. 1966 Sheet or:

Z 1' i l 80, Z iL v A 28 LAFAYETTE E. GILREATH CHARLES A. PoLLARo INVENTORS.

' ATTORNEY April 1, 1969' L. GILREATH ET AL 3,435,732

' HYDRAULICALLY POWERED DRILLING SUB Filed July 15, 1966 Sheet 2 of 2 LAFA YE TTE E. G/LREA Tl-l CHARLES H. POL LARD 1N VEN TORS Arm/war United States Patent 3,435,732 HYDRAULICALLY POWERED DRILLING SUB Lafayette E. Gilreath and Charles H. Pollard, Houston, Tex., assignors to Gilreath Hydraulics, Inc., Houston, Tex., a corporation of Texas Filed July 15, 1966, Ser. No. 565,485 Int. Cl. Ftllc 1/04 US. Cl. 91-135 1 Claim ABSTRACT OF THE DISCLOSURE A hydraulically powered drilling sub used in well drilling operations, constructed to be connected into a tubular drilling string to rotate the drilling bit while holding the string against rotation. The invention incorporates a hydraulic motor having a tubular barrel and a rotor in the barrel having radially movable blades between which fluid pressure is introduced from the string above while being discharged from the barrel below. The motor is provided with thrust bearings for holding the barrel and rotor against relative longitudinal movement and upper and lower elongated bearings above and below the rotor to hold the rotor against lateral movement in the barrel. Sealing means is provided at locations to prevent leakage between the barrel and rotor.

This invention relates to hydraulic motors and more particularly to a hydraulic motor which is constructed as a sub or connector for use in rotary drilling strings in the drilling of wells.

The invention finds particular utility as a motor to be connected into a drilling string at a convenient location to permit a portion of the string carrying a drilling bit to be rotated in a well bore while the remainder of the string is held against rotation.

In the drilling of wells by the rotary process it is customary to provide a string of drill pipe which carries a bit at its lower end, the entire length of the string being rotated from above while drilling fluid is circulated through the string and the annulus surrounding the same in the well bore. The rotation in this manner of very long strings of drill pipe, such as are often employed in the drilling of deep wells, requires the use of relatively massive equipment and a large expenditure of power, as well as presenting other disadvantages due to rotation of the entire string in the bore during the drilling operation.

The present invention has for an important object the provision of a hydraulic motor in the form of a drilling sub, which is adapted to be connected into a drilling string for operation by the pressure of drilling fluid circulated through the string, and by which a relatively short portion of the string with the drilling bit connected to its lower end may be rapidly rotated while the portion of the string above the sub may be held stationary.

Another object of the invention is to provide a hydraulic motor of the radially sliding vane type which is of elongated cylindrical shape and of relatively small diameter for use in a Well bore for operation by the pressure of fluid circulating through a drilling string.

A further object of the invention is the provision of a hydraulic motor of the type referred to having an outer barrel or stator and an inner mandrel or rotor rotatably mounted therein and which carries radially slidable vanes angularly spaced about the periphery of the mandrel and means for applying the pressure of the operating fluid radially outwardly to the vanes to hold the vanes in contact with the internal surface of the barrel during the intake or power portion of the rotational movement of the vanes while releasing such radial pressure to allow the vanes to move easily radially inwardly during the exhaust portion of the rotational movement of the vanes.

A still further object of the invention is to provide a hydraulic motor of the kind mentioned which is of simple design and rugged construction and in which the parts are easily replaceable for purposes of maintenance and repair.

Briefly described the hydraulically powered drilling sub of the invention comprises an outer elongated cylindrical stator or barrel which is adapted for connection at its upper end to the lower end of an upper portion of a drilling string above, in fixed relation thereto, and an inner elongated rotor or mandrel rotatably supported in the stator and extending downwardly beyond the lower end of the same for connection at its lower end to the upper end of a lower portion of the string to which a drilling bit is connected to rotate the bit with the rotor. The rotor and stator are spaced apart radially to provide an annular space surrounding the rotor in the stator and the stator carries a number of longitudinally extending, angularly spaced, radially slidable vanes Which extend across the annular space between the rotor and the internal surface of the stator, and means is provided for the admission to and exhaust from such annular space of fluid flowing downwardly through the string at locations to cause the rotor to rotate in the stator. The rotor is supported in the stator for rotation about a longitudinal axis common to both the rotor and the stator, and the wall of the stator varies in thickness radially inwardly from the outer periphery of the stator to form a cylindrical chamber in the stator which is eccentric relative to said common axis so that the vanes will be radially extended during one portion of their rotational movement in the stator and retracted during another portion of such rotation, whereby the admission of pressure to the chamber at one location between the vanes and the outflow of pressure from the chamber from between the vanes at another location will cause the rotor to rotate. Means is also provided for applying the pressure of fluid in the string to the vanes to extend the vanes to hold the outer edge portions of the vanes in tight engagement with the internal surface of the stator during the portion of their rotation during which power is applied to the vanes to rotate the rotor, and for releasing such pressure to reduce the outward pressure exerted by the vanes on the internal surface of the stator during the portion of their rotation during which fluid pressure is being exhauted from between the vanes.

Summary of the invention Briefly described the invention comprises a tubular barrel adapted to be connected at one end to the lower end of an upper section of a drilling string and a rotor rotata-bly mounted in the barrel and having a portion disposed in inwardly spaced relation thereto to form an annular chamber between the barrel and rotor, the rotor having radial, longitudinal slots and vanes slidably disposed in the slots-for radial movement in the chamber in engagement with the inner wall of the barrel to cause the rotor to rotate upon introduction of fluid into one end of the chamber between adjacent ones of the vanes while allowing an outflow of fluid from the other end of the chamber between adjacent ones of others of the vanes. Means is provided for attaching a drill bit to the rotor for rotation therewith while the string is held against rotation. The inflow of fluid into and the outflow from the chamber is con-trolled by end closure plates on the barrel at the ends of the rotor, each of which plates has an arcuate slot therethrough which is positioned in peripherally spaced relation to the slot of the other end plate. Similar slots are formed in the end plates for the introduction of fluid from the string into and the discharge of the same from the slots radially inwardly of the vanes to hold the vanes in extended position during a portion of their rotational movement in the chamber in response to the inflow of fluid from the string and to allow retraction of the vanes in the clots during another portion of such rotational movement. The rotor is held by thrust bearings against longitudinal movement in the barrel and elongated bearings are provided above and below the rotor to hold the rotor against lateral movement in the barrel. Seal forming means is also provided to prevent leakage of fluid from the chamber between the rotor and barrel.

The above and other obvious advantages of the invention will be evident from the following detailed description constituting a specification of the same when considered with the annexed drawings, wherein FIGURE 1 is a fragmentary side elevational view, partly in cross-section, of an upper end portion of the hydraulically powered drilling sub of the invention;

FIGURE 1-A is a view similar to that of FIGURE 1 showing a lower end portion of the sub, FIGURE l-A being a downward continuation of FIGURE 1;

FIGURE 2 is a cross-sectional view, taken along the line 22 of FIGURE 1, looking in the direction indicated by the arrows;

FIGURE 3 is a cross-sectional view, taken along the line 33 of FIGURE 2, looking in the direction indicated by the arrows;

FIGURE 4 is a cross-sectional view, taken along the line 4-4 of FIGURE 1, looking in the direction indicated by the arrows; and

FIGURE 5 is a cross-sectional view, taken along the line 55 of FIGURE 1, looking in the direction indicated by the arrows.

Referring now to the drawings in greater detail the hydraulically powered drilling sub comprises an elongated outer cylindrical stator or barrel member generally designated 10, which is threadably connected at its upper end to a tubular connector member 12 which also serves as a bearing enclosing member and Whose upper end is provided with an internally threaded box portion 14, for threadable connection to the lower end of a section of drilling string 16 above. At its lower end the barrel is threadably connected, as shown at 18, to a lower tubular bearing enclosing member 20.

Within the barrel or stator member 10, a rotor member is rotatably mounted, which is made up of an upper cylindrical stem portion 24 having a lower end recess 26 which is internally splined, and a lower tubular part 28 formed with an upper end portion 30 which is extended into the recess 26 and is externally splined as indicated at 32 for engagement with the internal splines of the part 24 to cause the parts to rotate together.

The stem 24 is surrounded by a sleeve type bearing, carried in the connector 12 and which may be of a usual type having an outer cylindrical shell 34, which carries an inner cylindrical bearing element 36 providing a surface of suitable seal forming material, such as rubber, plastic or the like.

The lower bearing enclosing part 20 of the barrel is similarly provided with a sleeve-like bearing surrounding the lower rotor part 28, and which is formed with an outer sleeve 38, within which a cylindrical bearing element 40 providing of seal forming material is carried. This lower bearing is seated at its lower end on an internal annular shoulder 42 formed on the outer part 20.

The lower rotor part has an external annular flange 44 thereon, mediate its ends, positioned below the internal shoulder of the part 20 upon which suitable bearings means such as the ball bearing 46 is seated between the shoulder 42 and flange 44, and similar bearing means 48 is seated on the upper end of a ring 50 threadably carried in the lower end of the part 20, between the ring and the lower face of the flange 44.

At its lower end the lower rotor part 28 is threadably attached to a connector member or sub 52 having a lower end, internally threaded box portion for connection to the upper end of a lower section 54 of the drilling string.

The upper part of the barrel or stator has an internal shoulder 56, and the upper rotor part 24 has an extended shoulder 58, upon which shoulders an upper ring or end closure plate 60 is carried, which is non-rotatatively secured to the stator, as by means of a pin 62, shown in FIGURES 2 and 3. The ring 60 is formed in two parts, the lower part 64 being of seal forming material, such as rubber or plastic, while the upper part 66 may be of a harder material, such as steel.

Above the ring 60 the connector member 12 is formed with a passageway 68 whose upper end is in communication with the interior of the drilling string above, and between the upper rotor part 24 and the barrel, there is an annular chamber 70 surrounding the rotor, as best seen in FIGURE 4.

At the lower end of the chamber 70, a ring or and closure plate 72, similar to the ring 60 is seated on the upper end of the outer part 20 of the barrel and an external shoulder 76 on the lower rotor part 28. The ring 72 is pinned to the barrel 10 in a similar manner to the ring 60, as by means of a pin 73, shown in FIGURE 5. The rings 60 and 72 form the upper and lower ends of the chamber 70 which is of varying thickness.

The ring 60 has an arcuate slot 78 therethrough which forms an inYet port in communication with the passage- Way 68 and leading into the chamber 70, and is also formed with an auxiliary inlet port 80 which likewise is in communication with the passageway 68. The ring 72 is of identical construction to the ring 60 but is reversed in position and has outlet ports 82 and 84 corresponding to the inlet ports 78 and 80, but which are positioned diametrically opposite the inlet ports, as shown in FIG- URE 5.

The upper rotor part 24 has an enlarged portion between the rings 60 and 72 which forms the inner wall of the chamber 70, and which is formed with angularly spaced, external, radially extending, longitudinal slots 86, extending from end to end of the chamber 70 and in each of which a blade or vane 88 is slidably disposed for radial movement. The blades 88 are of a width to extend across the width of the chamber 70 at the widest part of the chamber and to leave a clearance space behind the blades in the slots 66 when the blades are in their innermost position in the slots, as seen in FIG- URE 4. The arrangement is such that the clearance spaces radially inwardly of the blades 88 in the slots 86 will be in communication with the auxiliary inlet port 80 of the ring 60 so that the blades will be held extended during the portion of the movement of each blade during which fluid under pressure is being introduced into the chamber 70 to apply a rotative force to the blade, and will be in communication with the auxiliary outlet port 84 to allow the exhaust of pressure from behind each blade during that portion of the movement of the blade during which the rotative force is not being applied thereto.

The rotor may be formed with diametrically extending openings 87 opening into the inner ends of opposite ones of the slots 86, as shown in dotted lines in FIGURE 4, in which pins 89 are slidably disposed, which pins are positioned to engage the inner edges of the blades to cause the blades to move together in the slots. By this means the inward movement of one blade is transmitted to the opposite blade to impart outward movement thereto, so that sticking of the blades in the slots will be prevented.

The outlet ports 82 and 84 are in communication with a passageway 92 between the lower rotor part 28 and the lower barrel port 20 and from which a passageway 94 leads into the interior of the lower rotor part, whereby fluid may flow out of the chamber 70 between the blades 88 through ports 82 and 84 during the non-power portion of the movement of the blades.

The inlet ports 78 and 80 may be of substantially the same or somewhat different angular extent and the outlet ports 82 and 84 may be of similar length, so that an out-ward pressure will be exerted on the blades 88 to hold the same tightly against the inner surface of the barrel during the application of rot-ative force to the blades and to relieve such outward pressure to reduce pressure of the blades against the barrel during the time when such rot-ative force is not being applied to the blades.

In the operation of the motor, the barrel is connected to the lower end of an upper section of the drilling string for lowering therewith into a well bore, while the rotor is connected to the upper end of a lower section of the string to be rotated. With the motor thus incorporated in the string and positioned in the well, fluid may be circulated downwardly through the string to apply a rotative force to the blades 88 in the chamber 70, through the ports 78 and 80, the blades being tightly held against the inner face of the barrel during the application of such rotative force, while fluid is allowed to flow out of the chamber from between the blades and from the clots behind the blades during the time that such rotative force is not being applied.

It will be evident that the motor may be reversed by merely changing the direction of flow of the fluid therethrough, as by circulating fluid downwardly about the string and upwardly therethrough, should it be desired to reverse the direction of rotation of the drilling bit or other equipment being operated.

It will thus be apparent that the invention provides a hydraulic motor which is of simple design and rugged construction, capable of long withstanding the extreme conditions of wear and hard usage to which well equipment of this character is customarily subjected, and wherein the parts are readily replaceable for purposes of maintenance and repair.

The invention is disclosed herein in connection with a particular embodiment of the same, which is intended by way of example only, it being evident that various changes can be made in the construction and arrangement of the parts, within the spirit of the invention and the scope of the appended claim.

Having thus clearly shown and described the invention, what is claimed as new and desired to secure by Letters Patent is:

1. A hydraulically powered drilling sub comprising, an elongated tubular barrel member adapted to be connected at one end to the lower end of an upper section of a drilling string for lowering therewith in a well bore, a rotor member rotatably mounted in the barrel said rotor member having upper and lower cylindrical end portions rotatable within the barrel and being adapted to be connected at its lower end to the upper end of a lower section of said string, said barrel member and rotor member being shaped to form between them an annular chamber whose radial width varies peripherally, upper and lower, annular closure plates carried by the barrel member at the opposite ends of the chamber, seal forming means positioned to form a fluid tight seal between each closure plate and the adjacent end of the rotor member, radially extending vanes in and extending from end to end of said chamber in radial sliding engagement with and rotatable with said rotor member and whose outer longitudinal edges are in engagement with the inner face of the outer wall of the chamber, said upper closure plate and seal forming means having an arcuate slot therethrou-gh in communication with the interior of the string above the barrel member and said chamber and said lower closure plate and seal forming means having an arcuate slot therethrough at a location spaced peripherally of the slot of said upper closure plate and in communication with said chamber and the interior of the string below the barrel, said sub including additional seal forming means comprising upper and lower elongated cylindrical bearing members interposed between said upper and lower end portions of said rotor member and said barrel member, each bearing member including an inner surface of seal forming material, said seal forming members being positioned to form fluid tight seals respectively between said barrel member and rotor member immediately above said upper closure plate and immediately below said lower closure plate.

References Cited UNITED STATES PATENTS 348,879 9/1886 Austin 91-129 2,155,205 4/1939 Rodgers 91-129 3,238,848 3/1966 Bent 91-138 3,314,333 4/1967 King et al. 91-129 2,984,219 5/1961 Mitchell 91-149 3,120,154 2/1964 Gilreath 91-135 EVERETTE A. POWELL, JR., Primary Examiner.

US. Cl. X.R. 91-121 

